Fasting Not Required for Cholesterol Test

Cholesterol tests are used as a key part of assessing a patient's risk of cardiovascular problems. Fasting has been recommended as it had been thought the body needed enough time to digest food in the system and to clear any fatty particles from the blood. This was in order to produce an accurate reading of so-called "bad" cholesterol -- or low-density lipoprotein (LDL).

However, Naveed Sattar, Professor of Metabolic Medicine and Chris Packard, an Honorary Professor in Developmental Medicine, both of the University of Glasgow, together with researchers from the University of Cambridge, found that test results were just as accurate without fasting.

"After analysing data from 300,000 patients, the results were just as accurate if the patient had eaten before the test," said Professor Sattar.

Lead researcher John Danesh, Professor of Epidemiology and Medicine at the University of Cambridge, continued, "For decades, people have been asked to fast overnight before their cholesterol tests. Our findings indicate that cholesterol measurements are at least as good -- and probably somewhat better -- when made without fasting."

The study also adds to the ongoing controversy over whether testing for blood proteins called apolipoproteins is a more reliable way of predicting heart risk than cholesterol testing.

"The studies showed that analyzing "good" cholesterol -- or high-density lipoprotein (HDL) in conjunction with LDL was just as informative as testing for apolipoproteins AI and B. Furthermore our paper shows that once "bad" cholesterol and "good" HDL-cholesterol are known, using the levels of triglycerides or fat in the blood, as a means to predict the risk of heart disease, is unhelpful," said Professor Sattar.

Professor Peter Weissberg, Medical Director of the British Heart Foundation, which funded the study, said, "Given the pressure the NHS is under, it is good news that doctors don't need to spend money on setting up more sophisticated tests based on apolipoproteins. But the study underlines the importance of all GP's being able to measure HDL cholesterol as well as total cholesterol in order to make the best predictions about heart disease risk."

The Emerging Risk Factors Collaboration. Major lipids, apolipoproteins, and risk of vascular disease. JAMA 2009; 302: 1993-2000